1. Field of the Invention
This invention relates to a novel toner used for image forming processes such as electrophotograph, electrostatic recording, magnetic recording and the like and in image forming processes using the same.
2. Description of Related Art
In the art of electrophotograph, properties of a photoconductive material such as cadmium sulfide, polyvinylcarbazole, selenium, zinc oxide and the like are utilized to form an electrostatic latent image. For example, electric charge is uniformly applied to a layer of photoconductive material; image exposure is then effected to form an electrostatic latent image; the latent image is subsequently developed by the use of toner particles having a charge of opposite polarity to that of the latent image (having a charge of identical polarity in the case of reversal development); and, if necessary, the image is transferred to a receiving sheet followed by fixing.
When an apparatus having a transfer step is employed, it is usual that the toner not transferred to a receiving sheet and remaining on the photosensitive member is removed and the photosensitive member is repeatedly used.
As the method for removing the toner remaining on a photosensitive member, there may be usually used a blade cleaning method, fur brush cleaning method, magnetic brush cleaning method, abrading roller cleaning method and the like. These methods are carried out by contacting the cleaning member with the photosensitive member. In these methods, the cleaning member is pressed to the photosensitive member at an appropriate pressure so that the photosensitive member is subjected to abrasion and the toner attaches fixedly to the photosensitive member while the cleaning member is used repeatedly. For example, Japanese Patent Application Laid-open No. 47345/1973 proposes that, for the purpose of avoiding the fixing of toner to a photosensitive member, both a friction decreasing material and an abradant material are added to a developer. Indeed, this proposal is effective to obviate the fixing of toner to a photosensitive member, but there still remains the following problem.
When the friction decreasing material is added in an amount enough for obviating the toner fixing phenomenon, materials of low electrical resistance such as paper powders, ozone addition product and the like can not be easily removed. These materials are formed on or attached to the surface of a photosensitive member while the photosensitive member is used repeatedly, and, in particular, latent images formed on the photosensitive member are markedly deteriorated by the materials of low electrical resistance under the conditions of high temperature and high humidity. The amounts of the friction decreasing material and the abradant material are so delicate that a toner of stable characteristics can be obtained with significant difficulty.